See http://www.w3.org/XML/XProc/2006/05/11-minutes.html
W3C[1]
- DRAFT -
XML Processing Model WG
Meeting 20, 11 May 2006
Agenda[2]
See also: IRC log[3]
Attendees
Present
Murray, Norm, Henry, Alessandro, Richard, Rui, Alex
Regrets
Andrew, Michael, Paul
Chair
Norm
Scribe
Norm
Contents
* Topics
1. Accept this agenda?
2. Accept minutes from the previous teleconference?
3. Next meeting: 18 May 2006
4. Face-to-face
5. Review of open action items
6. Issue 3089: What version/subset of XPath is used in conditionals?
7. Issue 3198: Functional components?
8. Issue 3199: How do pipeline parameters, inputs, and outputs
interact?
9. Any other business?
* Summary of Action Items
----------------------------------------------------------------------
Accept this agenda?
-> http://www.w3.org/XML/XProc/2006/05/11-agenda.html
Accepted.
Accept minutes from the previous teleconference?
-> http://www.w3.org/XML/XProc/2006/05/04-minutes.html
Accepted.
Next meeting: 18 May 2006
Already regrets from: Andrew, Michael, Henry
Face-to-face
Please register: http://www.w3.org/2002/09/wbs/38398/XProcFTF2/[6]
Local arrangements: http://www.w3.org/XML/XProc/2006/08/02-04-f2f.html[7]
Norm hopes we can nail down the transport next week.
Review of open action items
1. A-19-01[8]: Alex to send mail describing his ideas about variables.
* Continued
2. A-19-02[9]: Norm to create an issue about the
variable/parameter/input/output binding framework.
* Completed
3. A-18-01[10]: Alex to create an issue about the possibility of
functional components
* Completed
4. A-17-02[11]: Murray to provide local arrangements info for August
* Completed
5. A-13-01[12]: MSM to draft a complete table; ETA: 15 June 2006
* Continued.
Issue 3089: What version/subset of XPath is used in conditionals?
-> http://www.w3.org/Bugs/Public/show_bug.cgi?id=3089
MoZ: are you trying to dial in and not getting through the bridge?
Norm: Three possibilities, 1) use someone else's streaming subset, 2)
invent our own, 3) use full XPath and leave it as a QoI issue
Alex: Although I use a streaming subset, I think that's an optimization. I
think we shouldn't have a subset.
Norm: I can find off-the-shelf full XPath 1.0 implementations, so I think
that answer makes it easiest to get started
... Is there anyone that thinks we need to define a subset?
Henry: I'm uncomfortable, but I'm willing to leave it for CR.
Norm: That works for me.
Richard: Do we have a good idea of what circumstances these XPaths are
used in
Norm: Off the top of my head, we've got: conditionals, peepholing
Richard: Also the "replacement" component
... It's possible that that's a component by itself.
Norm: so those wouldn't have to be the same.
Richard: I think I'm happy for it to be full XPath 1.0 and I can detect
some streamable queries.
Proposal: We will use XPath 1.0 in our language
Alessandro: I think it will be interesting to have XPath 1.0 vs XPath 2.0
question
Alessandro: At least in the environment I am working in, off-the-shelf 2.0
implementations are easy to come by.
Norm: Do you have a use case in mind for pipeline conditionals?
Alessandro: Not off the top of my head
Alex: We could declare what version of XPath the pipeline uses and
implementations can reject pipelines they can't support.
Richard: Isn't it the case that if you have XPath 2.0, you have to worry
about whether the data has schema type and so on.
... I know that there are XSLT 2.0 implementations that don't support the
schema stuff and can give different answers.
... If we introduce XPath 2.0 are we introducing new levels of
conformance.
Norm: Yes, I think they would.
... This seems useful and interesting, but not necessary.
Norm observes, in response to Richard, that having XPath 2.0 would mean
that the pipeline engine would have to be able to import schemas
Alessandro: In environments where 2.0 is available, requiring XPath 1.0
seems like a burden
Norm prefers a single choice for interoperability
Alex: By the time we become a recommendation, we have to have a cohesive
store around XSLT 2.0, XPath 2.0, XQuery, etc.
... I don't think we can push that to V.next, we need to come out with a
recommendation that works well with those technologies.
Norm: Wow. Ok.
Norm worries that dealing with those things in 1.0 makes our goal of
finishing this year hopeless.
Alessandro: I agree that there's complexity, but I think we should try
just a little bit harder to try to accommodate schemas and XPath 2.0
... It might be the case that we come to the conclusion that we can't do
it in 1.0
Murray: I would tend to agree with Norm, let's do something we can
accomplish in the timeframe we set out, even if it isn't' as grand and
robust and wonderful as we might achieve in the fullness of time.
... We can move onto the next stage afterwards.
Norm: Can Alex/Alessandro make some proposals to see if you can convince
us that using schemas, XPath 2.0, etc. is achievable in our timeframe?
Alessandro: yes
Alex: yes
Proposal: We will assume full XPath, not a streaming subset, in the
language (unless and until we get pushback from implementors)
Accepted.
Issue 3198: Functional components?
-> http://www.w3.org/Bugs/Public/show_bug.cgi?id=3198
We've already made a decision about this, this issue is just for the
future
Issue 3199: How do pipeline parameters, inputs, and outputs interact?
-> http://www.w3.org/Bugs/Public/show_bug.cgi?id=3199
We don't really have any clear ideas about exactly how these things fit
together yet
Norm reviews Richard's ideas that started this
Richard: Fundamentally, it must be possible to get some output into a
parameter.
... The simplest way to define a parameter is to give a literal value.
... The next way up would be to give an XPath and the output of some other
component to apply it to. It would evaluate the expression and the result
would be the value of the variable
... So the temporary file component could generate a document and the
XPath expression could be "."
... This means that all these things are connected by plumbing.
... Other people have mentioned at various times mechanisms for having
variables that are in scope, etc. But I think the simple method is a good
starting point.
Norm: I had in mind setting variables in general being specified with
XPaths (so that pipeline params could be composed from command line params
(for example) and others.
... I was thinking of evaluating them all with an empty document node as
the context.
... Extending that to allow them to specify an input document makes sense.
... Is that sufficient?
Henry: It ought to be possible in a pipeline definition to say that the
value of some step parameter is referred to at the pipeline level
Scribe isn't sure that he recorded Henry correctly
Norm: Parameters could have two attributes: value and select for literal
values and XPath expressions
Some discussion about how these things get connected together
syntactically.
Richard: I think the 90% case is that variables are constants. It's
reasonable for it to be slightly complicated.
<scribe> ACTION: Norm to write up his thoughts on parameters and inputs
[recorded in http://www.w3.org/2006/05/11-xproc-minutes.html#action02[16]]
Alex: This is related to the variables action that I have
Richard: It would be nice if this mechanism was extensible to being able
to having different variables in scope in different parts of the pipeline.
... But it's not immediately clear to me how it is. But maybe it is.
Any other business?
None.
Adjourned.
Summary of Action Items
[NEW] ACTION: Norm to write up his thoughts on parameters and inputs
[recorded in http://www.w3.org/2006/05/11-xproc-minutes.html#action02[17]]
**
[End of minutes]
----------------------------------------------------------------------
[1] http://www.w3.org/
[2] http://www.w3.org/XML/XProc/2006/05/11-agenda.html
[3] http://www.w3.org/2006/05/11-xproc-irc
[6] http://www.w3.org/2002/09/wbs/38398/XProcFTF2/
[7] http://www.w3.org/XML/XProc/2006/08/02-04-f2f.html
[8] http://www.w3.org/XML/XProc/2006/05/04-minutes.html#action01
[9] http://www.w3.org/XML/XProc/2006/05/04-minutes.html#action02
[10] http://www.w3.org/XML/XProc/2006/04/27-minutes.html#action01
[11] http://www.w3.org/XML/XProc/2006/04/20-minutes.html#action02
[12] http://www.w3.org/XML/XProc/2006/03/23-minutes.html#action01
[16] http://www.w3.org/2006/05/11-xproc-minutes.html#action02
[17] http://www.w3.org/2006/05/11-xproc-minutes.html#action02
[18] http://dev.w3.org/cvsweb/~checkout~/2002/scribe/scribedoc.htm
[19] http://dev.w3.org/cvsweb/2002/scribe/
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$Date: 2006/05/11 19:18:30 $